I can only name some German boardgames which we (family/friends) play quite often. I don't know if they're available in USA:
- Wikinger (Vikings)
- Carcassonne
- Thurn & Taxis
- Jenseits von Theben (East of Thebes) => actually not of German, but of Austrian origin
- Puerto Rico
- Die Säulen der Erde (The Pillars of the Earth)
and one, which you already named:
- The Settlers of Catan
(10 mio copies sold from 1996 to 2002, 8 mio. in Germany alone. I have to play it of course, although I don't really like it anymore, but everybody else around me still does).
But not only German games are very popular in Germany, also Monopoly and other classics. Boardgames are very popular over here.








